Variation in Colour of Pseudoterranova decipiens (Nematoda; Anisakidae) Larvae Correlates with Haemoglobin Concentration in the Pseudocoelomic Fluid

Abstract

Larval sealworm (Pseudoterranova decipiens) were collected from the fillets of Atlantic cod (Gadhus morhua) and the relationship between the colour of the nematodes, which varied from reddish brown to white, and the concentration of haemoglobin in their pseudocoelomic fluid was investigated. The colour of the haemoglobin, which makes up greater than 30% of the protein in the pseudocoelomic fluid, is derived from the heme group. As the heme copurifies with the protein and does not exist in the free form, colour variations in the nematode may, therefore, be due to differences in haemoglobin content. We investigate the possible regulation of levels of this protein and discuss the mechanisms by which this regulation would be achieved.